Former Rep. Eric Massa (D-N.Y.) has been under investigation for allegations that he groped multiple male staffers working in his office, according to three sources familiar with the probe.

The allegations surrounding the former lawmaker date back at least a year, and involve “a pattern of behavior and physical harassment,” according to one source. The new claims of alleged groping contradictstatements by Massa, who resigned his office on Monday after it became public that he was the subject of a House ethics committee investigation for possible harassment.